Translation of canal in Spanish

I hope you can understand the corrections this way... Two small errors. let me know if there is a word or sentence or phrase that you didn't understand! I will try to think more on the "since" question...
The first thing he wanted to show us was a war memorial for Cambodia's civil war. The war has ended only few years earlier and was still very present in the mind of the entire population.
The biggest city in Germany is Berlin. The other big cities are not as big but some of them are really nice. And especially the smaller cities here are very charming and worth visiting.